TVS diode

Discussion in 'General Electronics Chat' started by darkmatter, May 9, 2014.

  1. darkmatter

    Thread Starter New Member

    Dec 19, 2008
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    Hello Board;

    I have aTVS diode 1.5KE75A which is suppose to shunt about 20A in 100 ns . The clamp is at 103V , My question is when its in clamp mode for few nano seconds my power supply 60V is getting over volted to bout 43V , does this remaining 43v force transient current int my power supply if yes how to calculate. Sorry the question seems to be basic but I am struggling for 8 hours with this , hope to get some expert advice. Thanks.
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    It might, depending on the design of your supply.
     
  3. alfacliff

    Well-Known Member

    Dec 13, 2013
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    then why not get a tvs better suited for the job? one closer to 60 volts ?
     
  4. crutschow

    Expert

    Mar 14, 2008
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    What is the source of the transient?
     
  5. darkmatter

    Thread Starter New Member

    Dec 19, 2008
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  6. darkmatter

    Thread Starter New Member

    Dec 19, 2008
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    The source of transient is CDM.
     
  7. ErnieHorning

    Member

    Apr 17, 2014
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    I agree, if you’re measuring more than 72 volts (max for the part) even nanoseconds will likely compromise the part.
     
  8. crutschow

    Expert

    Mar 14, 2008
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    Okay. What's CDM?
     
  9. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Judging by the OP's name, perhaps that's "celestial dark matter" :D

    I don't think such an animal exists. All the link shows is a black box. The circuitry inside is unknown.
     
  10. darkmatter

    Thread Starter New Member

    Dec 19, 2008
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    CDM= contact discharge model .
     
  11. darkmatter

    Thread Starter New Member

    Dec 19, 2008
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    He , he he , perhaps darkmatter is not that a mystery in present days physics.The link about converter provides only specification. Can some one judge from these type of DC-DC. If I were to know the inside circuit what should I look inside for. I plan to disect one of these.
     
    Last edited: May 10, 2014
  12. darkmatter

    Thread Starter New Member

    Dec 19, 2008
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    Please find the Image below , which shows the I/P stage.
    [​IMG]

    Any Help!
     
  13. darkmatter

    Thread Starter New Member

    Dec 19, 2008
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    Pardon me , correction Charge device model.
     
  14. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Here's a sim of the application of a 4us 200V spike from a 0.1 Ohm output-impedance source to your input circuit. It shows the diode clamping V(in) at 103V, a diode current peak of ~900A, and the cap voltage V(out) reaching ~80V. That exceeds the rating of your circuit by some way.
     
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  15. darkmatter

    Thread Starter New Member

    Dec 19, 2008
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    Thanks, I downloaded LTspice as I have never used it before but got weared results. I couldnt cope with model file . Can you please share your .asm file with me .
     
  16. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Here's the asc file. Can't remember if the TVS model is an LTS native one or if it was third-party.
     
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